In the opening remarks of his contribution to this volume, Ralph O’Connor observes that there have been many developments in our understanding of the composition and transmission of medieval Gaelic narrative literature in recent decades, but that these advances have sometimes happened within different and distinct academic specialisms and have not always been communicated beyond disciplinary boundaries. O’Connor’s concern is the boundary between ‘historical’ and ‘literary’ fields of enquiry, and as he notes, ‘the aims of historical research and literary criticism are so different that even within the largely happy family of Celtic Studies there is still a risk of talking at cross-purposes, or not talking to each other at all’. The Ulidia conference series on the Ulster Cycle of tales has always been an opportunity for conversation across disciplines, as scholars bring their research interests, not only in history and literature, but also in placename studies, archaeology, comparative religion, linguistics, folklore and much more besides, to bear on a corpus of medieval texts and its later reflexes. Some of the essays presented here offer probing explorations of particular aspects of individual Ulster Cycle tales: Michael Clarke, for example, elucidates the idea of ‘barbarousness’ in the Middle Irish tale Mesca Ulaid (‘The Intoxication of the Ulstermen’) and Elizabeth Gray focuses on the character of Deirdre in Longes mac nUislenn (‘The Exile of the Sons of Uisliu’). Others turn their attention to the intellectual inheritance that influenced the authors of various Ulster Cycle narratives: Máire Herbert discusses the influence of the ‘Letter of Abgar’ tradition on the various versions of the death of Conchobar, and Daniel Watson situates the earliest extant death-tale of Cú Chulainn in the context of thinking about the ‘Six Ages of the World’ and Augustinian historiography. Some contributors look across the corpus, such as in Mary Leenane’s study of the presentation of Cú Chulainn across the Ulster Cycle and Patricia Ronan’s analysis of ‘conflict talk’ in seven different Ulster Cycle tales, or beyond the corpus, as with Kay Muhr’s study of the character of Dáire, not only in the Ulster Cycle but in legal and hagiographical texts. Of course, Táin Bó Cúailnge (‘The Cattle Raid of Cooley’) is a significant site of interest for many authors: Ralph Kenna, Pádraig MacCarron and Denis Casey offer an innovative network analysis of character interactions in the Táin, and Thomas O’Donnell considers the physiology of Cú Chulainn in the saga. The physical depiction of Cú Chulainn is also a concern for Gaël Hily, who examines the wider literary resonances of the ‘one foot, one hand, one eye’ motif. Some of the contributions deal with the afterlives of Ulster Cycle texts and characters: Cameron Wachowich, for example, presents a study of an Irish poem of the late twelfth or thirteenth century on an invasion of Ireland by the ‘King of Africa’, which deploys Ulster Cycle characters in intriguing ways, possibly for an English patron, John de Courcy. Breandán Ó Cróinín brings us right up to the present day with a study of modern Irish literary retellings of Ulster Cycle tales. With different approaches come different viewpoints on what the Ulster Cycle actually represents – a self-consciously crafted medieval literature, or the remnants of a more ancient mythology (or a bit of both). Chapters which take a comparative mythological or cosmological approach, such as those by Garrett Olmsted and Phillip A. Bernhardt-House, or that analyse a tale as a reflection of kingship ideology, such as Marion Deane’s, sit side by side with those that approach the Ulster Cycle as literature and/or a medieval form of historiography, and we hope that this juxtaposition will serve as an invitation to future interdisciplinary dialogue and shared insights. The present volume comprises many (though not all) of the papers presented at the fifth Ulidia conference, held at Maynooth University in 2016, and as with previous instalments in this series, includes papers which draw on a range of disciplines, some of which fall within the editors’ primary areas of expertise (literature, linguistics, history) but some of which draw widely from areas as diverse as statistical modelling and comparative mythology. Two of the three plenary lectures – by Máire Herbert and Ralph O’Connor – are included as chapters in this volume; the third, by Tomás Ó Cathasaigh, will appear in a forthcoming Festschrift. We are grateful to all the contributors for their patience, as the volume met with delays and setbacks, not least the COVID-19 pandemic, which slowed scholarly work for many people, and particularly those with caring responsibilities. During the lengthy gestation of this volume we witnessed the tragic passing of two of our contributors, and we offer our sincere condolences and thoughts to the loved ones of Marion Deane and Ralph Kenna. We are grateful to Daniel Büchner at curach bhán publications for his patience and expertise, and to the Department of Early Irish, Maynooth University, for financial support. Finally, we thank our colleagues in Roinn na Nua-Ghaeilge and the Department of Early Irish, Maynooth University, for their support of the conference from which these papers derive and for their ongoing collegiality over the years.